U.S. patent application number 14/812166 was filed with the patent office on 2016-02-04 for injection device and corresponding method for manufacturing same.
The applicant listed for this patent is Eberspacher Exhaust Technology GmbH & Co.KG. Invention is credited to Frank BERKEMER, David BINDER, Felix HACKLANDER, Konrad KLAUSA, Jurgen KOBE.
Application Number | 20160032808 14/812166 |
Document ID | / |
Family ID | 53442638 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160032808 |
Kind Code |
A1 |
KOBE; Jurgen ; et
al. |
February 4, 2016 |
INJECTION DEVICE AND CORRESPONDING METHOD FOR MANUFACTURING
SAME
Abstract
An injection device (14), for introducing a reducing agent (11)
into an exhaust gas stream (8) of an exhaust system (7) of an
internal combustion engine (1), has an exhaust pipe (15) for
guiding the exhaust gas stream (8), which has a connecting piece
opening (18) in a wall (17). A connecting piece (16) is inserted
with an inner end (19) into the connecting piece opening (18) and
is provided for connecting an injector (10) at an outer end (20).
Simplified assembly is achieved if the connecting piece (16) has,
at an inner end (19), a laterally projecting, fully
circumferentially extending collar (22). The collar (22) is in
contact, on an inner side (23) of the wall (17), with an opening
edge (24) enclosing the connecting piece opening (18) and is welded
to the wall (17).
Inventors: |
KOBE; Jurgen;
(Nurtingen-Raidwangen, DE) ; BERKEMER; Frank;
(Eningen u.A., DE) ; KLAUSA; Konrad; (Deizisau,
DE) ; BINDER; David; (Schramberg, DE) ;
HACKLANDER; Felix; (Esslingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eberspacher Exhaust Technology GmbH & Co.KG |
Neunkirchen |
|
DE |
|
|
Family ID: |
53442638 |
Appl. No.: |
14/812166 |
Filed: |
July 29, 2015 |
Current U.S.
Class: |
422/168 ;
29/890 |
Current CPC
Class: |
F01N 13/185 20130101;
Y02T 10/24 20130101; Y02T 10/12 20130101; F01N 3/2892 20130101;
F01N 2610/1453 20130101; F01N 13/1838 20130101; F01N 13/08
20130101; F01N 3/2066 20130101; F01N 2470/00 20130101; F01N 2450/22
20130101; F01N 13/1888 20130101 |
International
Class: |
F01N 3/20 20060101
F01N003/20; F01N 3/28 20060101 F01N003/28 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2014 |
DE |
10 2014 215 084.1 |
Claims
1. An injection device for introducing a reducing agent into an
exhaust gas stream of an exhaust system of an internal combustion
engine, the injection device comprising: an exhaust pipe for
guiding the exhaust gas stream, the exhaust pipe having a wall with
a connecting piece opening in the wall; and a connecting piece,
which is inserted with an inner end into the connecting piece
opening, the connecting piece being provided at an outer end for
connecting an injector, wherein the connecting piece has, at a
connecting piece inner end, a laterally projecting, fully
circumferentially extending collar, which collar is in contact on
an inner side of the wall with an opening edge enclosing the
connecting piece opening and which collar is welded to the
wall.
2. An injection device in accordance with claim 1, wherein the
collar is welded to the wall with a circumferential weld seam,
which circumferential weld seam is closed at the collar and is
located on an inner side of the wall.
3. An injection device in accordance with claim 1, further
comprising a static mixer inserted into the exhaust pipe in an area
of an outlet end of the exhaust pipe.
4. An injection device in accordance with claim 1, wherein the
exhaust pipe comprises a first shell and a second shell, which
extend each from an inlet end of the exhaust pipe to an outlet end
of the exhaust pipe, wherein only the first shell has the
connecting piece opening and is welded to the connecting piece.
5. An injection device in accordance with claim 4, further
comprising a static mixer inserted into the exhaust pipe in an area
of an outlet end of the exhaust pipe, wherein: the two shells are
fastened to one another along two mutually opposite connection
areas; and on an outer side, the mixer has two meshing areas, which
mesh each with one of the connection areas, whereby the mixer is
fastened to the exhaust pipe due to the two shells being fastened
to one another.
6. An injection device in accordance with claim 4, wherein the two
shells are fastened to one another along the respective connection
area by means of a weld seam, in which the respective meshing area
is integrated, such that the respective meshing area is fastened to
at least one of the two shells by means of the weld seam.
7. An injection device in accordance with claim 1, wherein the
connecting piece is arranged on the exhaust pipe such that a
central longitudinal axis of the connecting piece is sloped in
relation to a vertical direction extending radially to a central
longitudinal axis of the exhaust pipe in the area of the connecting
piece opening.
8. An injection device in accordance with claim 1, wherein: the
exhaust pipe has at least one arcuate portion; the connecting piece
opening is arranged axially aligned with an outlet end of the
exhaust pipe; and the connecting piece is straight and is aligned
coaxially with the outlet end of the exhaust pipe.
9. An injection device in accordance with claim 1, wherein: the
exhaust pipe has a first arcuate portion; the connecting piece
opening is arranged axially aligned with an outlet end of the
exhaust pipe; the exhaust pipe has a second arcuate portion; and
the connecting piece opening is arranged on a straight pipe section
formed between the first arcuate portion and the second arcuate
portion.
10. An injection device in accordance with claim 9, wherein at
least one of: the first arcuate portion and the second arcuate
portion are located in a common central longitudinal plane of the
exhaust pipe; the first arcuate portion and the second arcuate
portion have opposite curvatures; and the first arcuate portion and
the second arcuate portion have essentially equal curvatures in
terms of value.
11. A method for manufacturing an injection device for introducing
a reducing agent into an exhaust gas stream of an exhaust system of
an internal combustion engine, the method comprising the steps of:
providing the injection device with an exhaust pipe for guiding the
exhaust gas stream, which exhaust pipe has a connecting piece
opening in a wall; providing the injection device with a connecting
piece; inserting an inner end of the connecting piece into the
connecting piece opening to provide an outer end of the connecting
piece for a connection to an injector, wherein the step of
inserting comprises passing the connecting piece through the
connecting piece opening from an inner side of the wall until a
laterally projecting, fully circumferentially extending collar,
formed at the inner end of the connecting piece, comes into contact
with an opening edge enclosing the connecting piece opening on the
inner side of the wall; and welding the collar to the wall.
12. A method in accordance with claim 11, wherein the collar is
welded to the wall on the inner side of the wall.
13. A method in accordance with claim 12, wherein the collar is
welded to the wall by means of a weld seam extending on the collar
fully circumferentially.
14. A method in accordance with claim 11, wherein: the exhaust pipe
has a first shell having the connecting piece opening and a second
shell; the connecting piece is inserted into the connecting piece
opening before placing the second shell on the first shell, and the
connecting piece is welded to the first shell; and the second shell
is attached to the first shell after the connecting piece has been
welded to the first shell.
15. A method in accordance with claim 14, further comprising
providing a static mixer and inserting the static mixer into the
first shell or into the second shell after placing the second shell
on the first shell.
16. An injection device for introducing a reducing agent into an
exhaust gas stream of an exhaust system of an internal combustion
engine, the injection device being formed by the method steps
comprising: providing the injection device with an exhaust pipe for
guiding the exhaust gas stream, which exhaust pipe has a connecting
piece opening in a wall; providing the injection device with a
connecting piece; inserting an inner end of the connecting piece
into the connecting piece opening to provide an outer end of the
connecting piece for a connection to an injector, wherein the step
of inserting comprises passing the connecting piece through the
connecting piece opening from an inner side of the wall until a
laterally projecting, fully circumferentially extending collar,
formed at the inner end of the connecting piece, comes into contact
with an opening edge enclosing the connecting piece opening on the
inner side of the wall; and welding the collar to the wall.
17. An injection device in accordance with claim 16, wherein the
collar is welded to the wall on the inner side of the wall.
18. An injection device in accordance with claim 17, wherein the
collar is welded to the wall by means of a weld seam extending on
the collar fully circumferentially.
19. An injection device in accordance with claim 16, wherein: the
exhaust pipe has a first shell having the connecting piece opening
and a second shell; the connecting piece is inserted into the
connecting piece opening before placing the second shell on the
first shell, and the connecting piece is welded to the first shell;
and the second shell is attached to the first shell after the
connecting piece has been welded to the first shell.
20. An injection device in accordance with claim 19, further
comprising providing a static mixer and inserting the static mixer
into the first shell or into the second shell after placing the
second shell on the first shell.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn.119 of German Patent Application DE 10 2014 215 084.1
filed Jul. 31, 2014, the entire contents of which are incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention pertains to an injection device for
introducing a reducing agent into an exhaust gas stream of an
exhaust system of an internal combustion engine. The present
invention also pertains to a method for manufacturing such an
injection device.
BACKGROUND OF THE INVENTION
[0003] The introduction of a reducing agent into an exhaust gas
stream of an exhaust system is considered above all in so-called
SCR systems, where SCR denotes Selective Catalytic Reduction. A
liquid reducing agent, namely, preferably an aqueous urea solution,
is usually considered for use as a reducing agent. The reducing
agent evaporates in the exhaust gas stream and can react by
thermolysis and subsequent hydrolysis to form ammonia and carbon
dioxide. As a result, nitrogen oxides can be reduced into nitrogen
and water in an SCR catalytic converter.
[0004] An injection device suitable for introducing the reducing
agent into the exhaust gas stream usually comprises an exhaust pipe
for guiding the exhaust gas stream, which has a connecting piece
opening, as well as a connecting piece, which is connected with an
inner end to the connecting piece opening and which is provided at
an outer end for connecting an injector. The injector can then
inject the reducing agent into the exhaust gas stream being led in
the exhaust pipe through the connecting piece and through the
connecting piece opening.
[0005] The tight connection of the connecting piece to the exhaust
pipe is comparatively complicated, because the exhaust pipe usually
has a round cross section. Further, the connecting piece is not
preferably connected vertically or perpendicularly to an outer side
of the wall of the exhaust pipe, but sloped in relation to the
vertical direction. As a result, the geometric transition between
the exhaust pipe usually provided with a round cross section and
the connecting piece usually provided with a round cross section is
comparatively complicated. The manufacture of such an injection
device is comparatively complicated as a result. In particular, a
relatively large flange is necessary at the inner end of the
connecting piece in order to make it possible to weld this
connecting piece on the outer side of the exhaust pipe. If,
however, the connecting piece is manufactured integrally with the
flange as a cast part, the connecting piece will have a relatively
large thermal mass. As a result, the connecting piece can absorb a
relatively large quantity of heat during the operation of the
exhaust system and conduct this heat to its outer end and transmit
it to the injector there. Since the injector is comparatively
heat-sensitive, a large thermal mass of the connecting piece may
lead to damage to or destruction of the injector.
[0006] As an alternative, it is conceivable, for example, to use a
separate adapter, which has, on the one hand, the flange and is
adapted to the geometry of the outer side of the exhaust pipe, and
is adapted, on the other hand, to the geometry of the inner end of
the connecting piece. The adapter can then be welded relatively
easily to the connecting piece, on the one hand, and to the exhaust
pipe, on the other hand. As a result, the connecting piece can be
embodied with a markedly reduced wall thickness, which reduces the
thermal mass of said connecting piece. However, this manufacturing
operation is comparatively complicated because of the increased
number of parts, because relatively many steps and components are
necessary.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide an improved
embodiment, which is characterized especially by reduced
manufacturing costs, for an injection device of the above-described
type and for a corresponding manufacturing method.
[0008] According to the invention, an injection device is provided
for introducing a reducing agent into an exhaust gas stream of an
exhaust system of an internal combustion engine. The injection
device comprises an exhaust pipe for guiding the exhaust gas
stream, the exhaust pipe having a wall with a connecting piece
opening in the wall. A connecting piece is inserted with an inner
end into the connecting piece opening. The connecting piece is
provided at an outer end for connecting an injector. The connecting
piece has, at a connecting piece inner end, a laterally projecting,
fully circumferentially extending collar. The collar is in contact,
on an inner side of the wall, with an opening edge enclosing the
connecting piece opening. The collar is welded to the wall.
[0009] The present invention is based on the general idea of
equipping the connecting piece at its inner end with a laterally
projecting collar, which extends circumferentially fully in the
circumferential direction of the connecting piece and which comes
into contact with an inner side of the wall of the exhaust pipe in
the area of an opening edge enclosing the connecting piece opening.
Further, it is proposed that the connecting piece be welded to the
exhaust pipe in the area of its collar. The fact that the collar is
formed integrally on the connecting piece leads to a one-piece
component that is uniform in terms of the material. The collar may
be formed, for example, by plastic deformation on the connecting
piece. It may likewise be a one-piece, integral cast part. Thus,
ultimately only two components are necessary, namely, the
connecting piece with the collar, and the exhaust pipe, which must
be fitted together. The positioning of the collar on the inner side
of the wall of the exhaust pipe is of decisive significance,
because pressure loads, which develop in the interior of the
exhaust pipe, are supported via the collar on the opening edge and
hence as forces of pressure on the exhaust pipe. Thus, such forces
of pressure do not load the welded connection between the collar
and the exhaust pipe or do so only negligibly, so that a stable and
tight connection can be created here in a durable manner between
the connecting piece and the exhaust pipe. In addition, only a
single welded connection is necessary between the connecting piece
and the exhaust pipe due to the suggestion according to the present
invention in order to fasten the connecting piece to the exhaust
pipe. However, it is decisive that the collar, which represents a
flange located on the inside, can be dimensioned as a relatively
small collar, so that the thermal mass of the connecting piece with
the collar is ultimately reduced to the extent that the risk of
damage to the injector due to overheating during the operation of
the exhaust system is reduced. On the whole, an injection device
that can be manufactured at a low cost is thus presented. The
method for manufacturing this injection device can likewise be
carried out at a comparatively low cost.
[0010] The collar can be manufactured in an especially simple
manner such that it is formed in terms of its geometry
complementarily to the inner side of the wall in the area of the
opening edge. In this way, a large-area supporting of the collar on
the inner side of the wall can be achieved in an especially simple
manner.
[0011] Corresponding to an advantageous embodiment, the collar may
be welded to the wall by means of a weld seam that extends
circumferentially as a closed seam on the collar, the weld seam
being located on the inner side of the wall. In this way, the weld
seam can be manufactured in an especially simple manner especially
in case of collars formed complementarily to the inner side of the
wall, in order to generate sufficient strength and sufficient
tightness.
[0012] In another embodiment, the exhaust pipe may be assembled
from a first shell and a second shell, wherein the two shells
extend each from an inlet end of the exhaust pipe to an outlet end
of the exhaust pipe. Only the first shell contains the connecting
piece opening, and the connecting piece is welded only to the first
shell. It is possible, in particular, due to the two-shell design
of the exhaust pipe to mount the connecting piece on the first
shell and to weld to it same when the exhaust pipe is not yet
assembled. As long as the second shell is not mounted on the first
shell, the exhaust pipe is open over its entire length, as a result
of which its inner side is especially readily accessible for
inserting the connecting piece into the connecting piece opening
and to weld the collar to the wall of the exhaust pipe. Even though
a plurality of individual parts are present due to the exhaust part
comprising a plurality of parts, improved manufacturability is
achieved, on the whole, because, for example, the connecting piece
can be inserted through the connecting piece opening from the
inside in a more simple manner.
[0013] In another embodiment, a static mixer may be inserted into
the exhaust pipe in the area of an outlet end of the exhaust pipe.
Such a static mixer is designed such that it supports, on the one
hand, the evaporation of the reducing agent, which is optionally
introduced in the liquid form, and improves, on the other hand, the
mixing of the reducing agent with the exhaust gas stream. Such a
static mixer represents a separate component, which is inserted
into the exhaust pipe. Such a static mixer may preferably have a
plurality of guide blades, which are arranged in a star-shaped
pattern and which have especially a pitch in the same direction in
relation to the exhaust gas stream, and as a result of which the
exhaust gas stream will be imparted a twist while it is flowing
through the mixer. The guide blades may be arranged geometrically
such that the cross section of the exhaust pipe, through which the
flow takes place, is opaque in the axial direction, i.e., in the
principal direction of flow. Liquid droplets being entrained in the
exhaust gas stream thus inevitably reach the guide blades. Since
these are heated by the exhaust gas stream, the guide blades bring
about evaporation of the liquid reducing agent impacting on
same.
[0014] The integration of such a mixer within the injection device
simplifies the subsequent mounting of the injection device in the
exhaust system. For example, the injection device is installed in
the exhaust system directly upstream of an SCR catalytic converter,
so that the outlet end of the exhaust pipe is connected directly
with an inlet end of the SCR catalytic converter.
[0015] According to a variant, the mixer can be installed
especially advantageously in the two-shell exhaust pipe. Provisions
may be made for this for the two shells to be fastened to one
another along two mutually opposite connection areas, the two
connection areas extending each from the inlet end of the exhaust
pipe to the outlet end of the exhaust pipe.
[0016] Further, the mixer may have on its outer side two meshing
areas, which mesh each with one of the connection areas, preferably
such that the mixer is fastened to the exhaust pipe by the
fastening of the two shells to one another.
[0017] Provisions may preferably be made for the two shells to be
fastened to one another along the respective connection area by
means of a continuous weld seam, into which the respective meshing
area is integrated. Due to this integration of the respective
meshing area within the weld seam of the corresponding connection
area, the respective meshing area is ultimately fastened and hence
welded to at least one of the two shells, preferably to two shells,
by means of the weld seam.
[0018] In another embodiment, the connecting piece may be arranged
on the exhaust pipe such that a central longitudinal axis of the
connecting piece is inclined in relation to a vertical direction
extending radially to the central longitudinal axis of the exhaust
pipe in the area of the connecting piece opening. For example, a
slope angle of 30.degree. to 60.degree. is conceivable. The inner
end of the connecting piece and the collar can be readily adapted
geometrically to the respective desired slope angle, which
simplifies the mounting of the connecting piece on the exhaust
pipe.
[0019] In another embodiment, the exhaust pipe may have at least
one arc, and the connecting piece opening is arranged axially
aligned with an outlet end of the exhaust pipe in this case.
Further, the connecting piece may be optionally straight and
aligned coaxially with the outlet end of the exhaust pipe. The
provision of such an arc in the exhaust pipe makes it possible,
especially in connection with a sloped arrangement of the
connecting piece on the exhaust pipe, to generate injection of the
reducing agent that is oriented concentrically to the central
longitudinal axis of the exhaust pipe. For example, an injection
direction of the injector may be aligned such that it extends
coaxially to the central longitudinal axis of the connecting piece
and is correspondingly also aligned coaxially with the outlet end
of the exhaust pipe. It is achieved in this manner that the
injected reducing agent travels over the longest possible path
before it impacts on the wall of the exhaust pipe or the mixer.
[0020] In another advantageous embodiment, the exhaust pipe may
have a first arc (first arcuate portion), and the connecting piece
opening is arranged now axially aligned, especially coaxially
aligned, with an outlet end of the exhaust pipe. Further, the
exhaust pipe may have a second arc (second arcuate portion)
upstream, of the first arc, and the connecting piece opening is
arranged on a straight pipe section formed between the first arc
and the second arc. The fact that the connecting piece is arranged
on a straight pipe section simplifies the mounting of the
connecting piece. The provision of two arcs in the exhaust pipe
simplifies, by contrast, the mounting of the injection device in
the exhaust system.
[0021] The first arc and the second arc may preferably be located
in a common central longitudinal plane of the exhaust pipe. A
two-fold, two-dimensional deflection of the exhaust gas stream is
thus essentially achieved, but no three-dimensional deflection.
[0022] The first arc and the second arc may preferably have
opposite curvatures. It is achieved hereby that an inlet end of the
exhaust pipe and an outlet end of the exhaust pipe have only a
comparatively small offset, which simplifies the integration of the
injection device in the exhaust system.
[0023] Corresponding to another variant, the first arc and the
second arc may have essentially equal curvatures in terms of value.
As a consequence, the direction of flow of the exhaust gas stream
at the inlet end is largely parallel to the direction of flow of
the exhaust gas stream in the outlet end. This measure also leads
to a simplified integration of the injection device in the exhaust
system.
[0024] The method according to the present invention for
manufacturing such an injection device is characterized in that the
connecting piece is passed through the connecting piece opening
from an inner side of the wall up to a laterally projecting, fully
circumferential collar, formed at the inner end of the connecting
piece, on the inner side of the wall at an opening edge enclosing
the connecting piece opening. Further, the collar is subsequently
welded to the wall. It is achieved through this mode of
construction that pressure loads of the connection between the
connecting piece and the exhaust pipe are transmitted in a
positive-locking manner between the collar and the opening edge
without the welded connection between the connecting piece and the
exhaust pipe being critically loaded thereby.
[0025] Corresponding to an advantageous embodiment, the collar may
be welded to the wall on the inner side of the wall. This means
that the welded connection is prepared from the inside, i.e., from
the interior of the exhaust pipe. The establishment of a
sufficiently tight connection between the collar and the wall can
be simplified hereby. In particular, the connecting piece does not
cause any disturbance in case of this procedure when preparing the
welded connection.
[0026] According to another variant, the collar may be welded to
the wall by means of a weld seam extending fully circumferentially
on the collar. Such a circumferentially extending weld seam brings
about the necessary tightness between the connecting piece and the
exhaust pipe.
[0027] According to another embodiment, in which the exhaust pipe
has a first shell having the connecting piece opening and a second
shell, the method can be carried out such that the connecting piece
is inserted into the connecting piece opening before placing the
second shell on the first shell and is welded to the first shell.
The second shell can then be attached to the first shell after
welding the connecting piece to the first shell. For example, the
second shell is also welded to the first shell, and corresponding
weld seams are preferably prepared on an outer side of the exhaust
pipe. With the second shell missing, the mounting of the connecting
piece is simplified, because the inner side of the exhaust pipe is
especially readily accessible as a result.
[0028] Corresponding to a variant, a static mixer may be inserted
into the first shell or into the second shell in the area of an
outlet end of the exhaust pipe prior to the second shell being
placed on the first shell. To simplify the fixation of the mixer on
the exhaust pipe, the mixer may have two radially projecting
meshing sections, which mesh with the connection between the first
shell and the second shell, so that the mixer is also fixed on the
exhaust pipe due to the fixation of the first shell on the second
shell.
[0029] It is apparent that the above-mentioned features, which will
also be explained below, may be applied not only in the particular
combination indicated but in other combinations or alone as well,
without going beyond the scope of the present invention.
[0030] Preferred exemplary embodiments of the present invention are
shown in the drawings and will be explained in more detail in the
following description, where identical reference numbers designate
identical or similar or functionally identical components. The
various features of novelty which characterize the invention are
pointed out with particularity in the claims annexed to and forming
a part of this disclosure. For a better understanding of the
invention, its operating advantages and specific objects attained
by its uses, reference is made to the accompanying drawings and
descriptive matter in which preferred embodiments of the invention
are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In the drawings:
[0032] FIG. 1 is a highly simplified, circuit diagram-like
schematic view of an internal combustion engine with an exhaust
system, which contains an injection device;
[0033] FIG. 2 is an isometric view of the exhaust system in the
area of the injection device, wherein an exhaust pipe of the
injection device is shown as a transparent pipe; and
[0034] FIG. 3 is an isometric exploded view of the injection
device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Referring to the drawings, according to FIG. 1, an internal
combustion engine 1, which may be preferably used in a motor
vehicle, comprises an engine block 2, which contains a combustion
chamber 4 each in a plurality of cylinders 3. Pistons, not shown
here, are mounted in the cylinders 3 with adjustable stroke. A
fresh air feed unit 5 is used to feed fresh air to the combustion
chambers 4. A corresponding fresh air stream 6 is indicated by an
arrow in FIG. 1. An exhaust system 7 is used to remove exhaust gas
from the combustion chambers 4. A corresponding exhaust gas stream,
is indicated by an arrow in FIG. 1. The exhaust system 7 may be
equipped with an SCR system 9, which comprises an injector 10 for
introducing a reducing agent 11 into the exhaust gas stream 8 as
well as an SCR catalytic converter 12. In addition, a static mixer
13, which is arranged between the injector 10 and the SCR catalytic
converter 12 in relation to the direction of flow of the exhaust
gas stream 8, may be optionally provided. An injection device 14,
which has an exhaust pipe 15 for installing the injection device 14
in the exhaust system 7 as well as a connecting piece 16 for
connecting the injector 10, is provided in the SCR system 9 being
shown here. In addition, the mixer 13 is a part of the injection
device 14 in the example being shown here.
[0036] According to FIGS. 2 and 3, the injection device 14
comprises the exhaust pipe 15 for guiding the exhaust gas stream 8.
A wall 17 of the exhaust pipe 15 has a connecting piece opening 18.
The wall 17 radially defines a cross section of the exhaust pipe 15
through which the exhaust gas stream 8 can flow. The connecting
piece 16 is inserted with an inner end 19 into the connecting piece
opening 18 and is designed at an outer end 20 for connecting the
injector 10. A corresponding connection piece 21, which simplifies
the connection of the injector 10, is arranged at the outer end 20
in the example shown in FIGS. 2 and 3. The connection piece 21 may
be a separate component concerning the connecting piece 16, and it
is attached to the connecting piece 16 and is especially welded or
soldered to same. A screw connection is conceivable as well.
[0037] At its inner end 19, the connecting piece 16 has a collar
22, which laterally projects from the connecting piece 16 and
extends fully circumferentially in a circumferential direction of
the connecting piece 16. The collar 22 is arranged on an inner side
23 of the wall 17, which inner side is visible in FIG. 3, at an
opening edge 24, which encloses the connecting piece opening 18.
Furthermore, the collar 22 is welded to the wall 17. A
corresponding welded connection 25 is indicated in FIG. 2. The
welded connection 25 is preferably designed as a closed,
circumferentially extending weld seam 26. The weld seam 26 is
located on the inner side 23 of the wall 17.
[0038] In the example being shown, the exhaust pipe 15 comprises a
first shell 27 and a second shell 28. Both shells 27, 28 extend
from an inlet end 29 of the exhaust pipe 15 to an outer end 30 of
the exhaust pipe 15. The connecting piece opening 18 is formed on
the first shell 27, so that the connecting piece 16 is fastened
exclusively to the first shell 27.
[0039] The injection device 14 comprises in the example, besides,
the static mixer 13, which is inserted for this into the exhaust
pipe 15 in the area of the outlet end 30. The mixer 13 is a
separate component in relation to the exhaust pipe 15. The mixer 13
has a plurality of guide blades 31 arranged in a turbine-like
manner as well as a ring-shaped jacket body 32, which fully
encloses the guide blades 31 radially on the outside in the
circumferential direction of the pattern. Two diametrically
opposite meshing areas 33, which mesh on the respective side in a
connection area 34 between the two shells 27, 28, are formed on the
jacket 32. Due to the two shells 27, 28 being fixed to one another,
the mixer 13 is thus also fixed on the exhaust pipe 15. For
example, the two shells 27, 28 are welded to one another in the
respective connection area 34. A corresponding weld seam is
designated by 42 in FIG. 2. One such weld seam 42 each extends on
mutually opposite sides of the exhaust pipe 15 along the respective
connection area 34.
[0040] The exhaust pipe 15 has a first arc (arcuate portion) 35.
The connecting piece opening 18 is arranged axially aligned with
the outlet end 30 of the exhaust pipe 15. Further, the connecting
piece 16 is designed as a straight pipe and is aligned coaxially
with the outlet end 30. An axial direction 36 indicated in FIG. 1
thus extends concentrically through the connecting piece 16 and, in
the area of the outlet end 30, through the exhaust pipe 15. The
injector 10 can thus likewise introduce the reducing agent 11 into
the exhaust gas stream 8 concentrically to this axial direction
36.
[0041] The exhaust pipe 15 has here, in addition, a second arc
(arcuate portion) 37 as well as a straight pipe section 38 formed
between the first arc 35 and the second arc 37. The connecting
piece opening 18 is arranged on this straight pipe section 38. The
first arc 35 and the second arc 37 are in a common central
longitudinal plane of the exhaust pipe 15, which corresponds to the
drawing plane in FIG. 1, in the preferred example being shown here.
Further, the first arc 35 and the second arc 37 have opposite
curvatures. For example, the second arc 37 describes, when viewed
in the direction of flow of the exhaust gas stream 8 in FIG. 1, a
right curve, while the first arc 35 following it describes a left
curve. Further, provisions may be made for the first arc 35 and the
second arc 37 to have essentially equal curvatures in terms of
value. As a consequence, an inlet-side central longitudinal axis of
the exhaust pipe 15, which is present in the inlet end 29, is
oriented essentially in parallel to an outlet-side central
longitudinal axis of the exhaust pipe 15, which is present in the
outlet end 30.
[0042] The connecting piece 16 is preferably arranged on the
exhaust pipe 15 such that its central longitudinal axis 36, which
may hereinafter also be called the central longitudinal axis 36 of
the connecting piece, is inclined in relation to a vertical
direction, which extends radially to a central longitudinal axis 43
indicated in FIG. 1, which the exhaust pipe 15 has in the area of
the connecting piece opening 18 and which may hereinafter also be
called the central longitudinal axis 43 of the pipe. This slope
between the central longitudinal axis 36 of the connecting piece
and the central longitudinal axis 43 of the pipe and the vertical
direction thereof equals about 45.degree. in the example being
shown.
[0043] The curvatures of the two arcs 35, 37 may be equal or
essentially equal, i.e., have deviations of up to 20% and
preferably up to 10% in their radii of curvature.
[0044] As can, further, be determined from FIGS. 2 and 3, the
injection device 14 may have, besides, a connection pipe 39, which
is permanently connected with the exhaust pipe 15 in a suitable
manner and which can be connected to an adjacent component of the
exhaust system 7 by means of a clip 40. The connection pipe 29 may
be slotted laterally for this purpose at an end facing away from
the exhaust pipe 15. A corresponding slot 41 can be recognized in
FIG. 3.
[0045] The manufacture of the injection device 14 may proceed as
follows:
[0046] The connecting piece 16 is passed first through the
connecting piece opening 18 from the inner side 23 of the wall 17,
to the extent that the collar 22 provided at the inner end 19 comes
into contact with the opening edge 24 on the inner side 23 of the
wall 17. The insertion of the connecting piece 16 into the
connecting piece opening 18 is effected in the two-shell design of
the exhaust pipe 215 being presented here with the exhaust pipe 15
open, i.e., with the second shell 28 missing. Before placing the
second shell 28, the collar 22 is welded to the wall 17. The welded
connection 25 is prepared on the inner side 23. The weld seam 26 on
the collar 22 is preferably prepared as a collar extending fully
circumferentially. After welding the connecting piece 16 to the
first shell 27, the mixer 13, which is optionally present, can be
inserted into the first shell 27 or into the second shell 28. The
second shell 28 is subsequently attached to the first shell 27. The
two diametrically opposite connection areas 34, which extend each
from the inlet end 29 to the outlet end 30 of the exhaust pipe 15,
are preferably welded to one another.
[0047] After placing the second shell 28 on the first shell 27 and
before or after the welding of the two shells 27, 28 to one
another, the connection pipe 39 can be connected to the exhaust
pipe 15. For example, the connection pipe 39 can be inserted
axially into the inlet end 29 of the exhaust pipe 15 and welded to
it.
[0048] While specific embodiments of the invention have been shown
and described in detail to illustrate the application of the
principles of the invention, it will be understood that the
invention may be embodied otherwise without departing from such
principles.
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